Electron discharge device employing resonators



Ben. 16, 1947. A, v. HAEFF ELECTRON DISCHARGE DEVICE EMPLOYING RESONATORS 2 Sheets-Sheet 1 Filed Feb. 24, 1943 INVENTOR HnD Ew V HfiII-FF %wzzw N ATTORNEY D66 1%, 1947 A y, i-QAEFF 2,432,571

ELECTRON DISCHARGE DEVICE EMPLOYING RESONATORS Filed Feb. 2 -1, 1943 2 Sheets-Sheet 2 INVENTOR HDREuJ V. Hmz- Patented Dec. 16, 1947 ELECTRON DISCHARGE DEVICE EMPLOYING RESONATORS Andrew V. Haeif, Washington, D. (3., assignor to Radio Corporation of America, a corporation of Delaware Application February 24, 1943, Serial No. 476,893

19 Claims.

My invention relates to electron discharge devices and associated circuits particularly suitable for use at ultra high frequencies.

As the higher frequencies are approached inter-electrode capacities, inductance of electrode leads and capacities between the electrodes and associated circuits result in undesirable and uncontrolled coupling between input circuits and other circuits associated with the electrode system, since these inter-electrode capacities and lead inductances provide impedances common to the input circuit and the other circuits.

There has recently come into use for high frequency operation an electron discharge device utilizing a controlled beam of electrons, modulated by a conventional grid electrode connected to resonant cavity circuits or cavity resonators, energy being extracted from the modulated beam by induction by means of resonant cavity circuits.

In one form of such tube an elongated evacuated envelope has positioned at one end a cathode and grid and at the other end a collector. Positioned between the grid and collector is an output resonant cavity tank circuit surrounding the envelope and having a gap transverse to the beam of electrons. A screen and acceleraing electrode is positioned between the grid and the gap in the resonant cavity tank circuit. A concentric line input circuit is coupled between the cathode and the grid and this line is in turn surrounded by another resonant cavity circuit coupled to the screen. A device of this kind is described and claimed in my copending application Serial No. 375,029, filed January 18, 1941, and assigned to the same assignee as the present application. The grid and cathode leads extend through the envelope and are electrically connected to the concentric conducting member forming the resonant cavity circuits.

With this arrangement the grid lead provides a common coupling impedance between the input or cathode-grid circuit and the circuit associated with the screen electrode so that energy is fed back from the screen grid-control grid circuit through the common impedance to the input circuit. Depending upon the phase relationship of the fed back energy and the input signal voltage, either regeneration or degeneration may take place, causing either unwanted oscillations or excessive damping, or loading down of the input circuit.

Tubes of the kind described are primarily designed to eliminate input loading and to reduce ohmic and radiation losses by the proper arrangement of concentric line and resonant cavity tank circuits. However, as pointed out it is essential that the coupling between circuits and the control of energy feedback be provided in order to obtain satisfactory operation of the device. As the higher frequencies are approached the lead impedance and interelectrode capacitances and coupling between the tank circuits and the electrodes become the limiting factors in the operation of such devices.

In one form of an electron discharge device described and claimed in my co-pending application, Serial No. 437,634, filed April 4, 1942, and assigned to the same assignee as the pre:ent application, I show and describe a device in which the electrode leads, particularly those for the cathode and the grid, are extended through the envelope and form part of the circuits themselves, the leads acting as shields to prevent coupling between the input and output circuits. In the specific arrangement described the cathode leads are arranged in a circle and extend through one end of the tube envelope. The grid leads are positioned around the cathode leads and also extend through the tube envelope and form the walls of one of the resonators, shielding the cathode-grid or input circuit from the screen-control grid circuit, However, in a case of tubes of relatively small size, the concentric lead arrangement in the stem of the envelope may be difficult to manufacture and other construction is necessary.

In the form of tube described in my copending application, in order to provide feedback between the screen and input circuits, when it is desired to use the device as an oscillator, coupling 1oops are necessary, Which, to permit feedback in the proper phase and amount, require the use of a coaxial line cable which is adjustable, as well as adjustable coupling loops within the resonators.

It is, therefore, one of the principal objects of my invention to provide an electron discharge device particularly suitable for use at ultra high frequencies.

Another object of my invention is to provide such a device in which the electrode lead impedances and the interelectrode capacitances can be neutralized to permit control of the operation of the device at ultra high frequencies.

A further object of my invention is to provide such an electron discharge device and its associated circuit for operation at ultra high frequencies.

vide such a device in which restrictions placed on lead arrangements because of mechanical reasons are avoided.

Another object of my invention is to provide an electron discharge device utilizing circuits of the hollow resonant conducting type in which all of the circuits can be tuned without materially affecting the other circuits.

A further object of my invention is to provide a device of the type described in which the energy interchanged between the circuits may be controlled by tuning arrangements but without the need of extra coupling elements, such as ooaxial feed lines,

A still further object of my invention is to provide such an electron discharge device and associated resonant cavity circuits in which the transfer of energy between the screen circuit and the grid circuit can be accomplished without the use of external feed or coupling lines to control regeneration or degeneration.

A still further object of my invention is to provide means for coupling the output of an electron discharge device using resonant cavity circuits to another devic for amplification purposes or to an output circuit or load.

The novel features which I believe to be characteristic of my invention are set forth with particularity in the appended claims, but the invention itself will best be understood by reference to the following description taken in connection with the accompanying drawing in which Figure 1 is a longitudinal transverse section of an electron discharge device made according to my invention, Figures 2 and 3 are transverse sections taken along the line 22 and 33 of Figure 1, Figure 4 is a schematic diagram showing the equivalent circuits of parts of an electron discharge device made according to my invention and shown in Figure 1, Figure 5 is a more detailed equivalent circuit of one of the portions of a device made according to my invention, and Figure 6 is a schematic diagram of a complete electron discharge device made according to my invention and of its associated circuits and power supplies.

In Figure 1 I show a longitudinal section of an electron discharge device made according to my invention and of its associated circuits. The electrode system for providing the modulated electron beam is enclosed within an elongated envelope 18 containing at one end an indirectly heated cathode ll provided with heater [2. A cup-shaped control grid [3 surrounds and shields the cathode, and modulates the electron stream projected through the tube from cathode I3 to the collector l4 mounted at the other end of the tube. This collector may be provided with heat radiating fins l5 and have within it a secondary electron suppressing ring 16 normally maintained at a lower voltage than said collector. Positioned between the grid and the collector are a pair of accelerating electrodes I? and I8. The electron beam from the cathode II is modulated by the grid l3 and in passing through the accelerating electrodes I1 and I8 to the collector' l4 during operation of the device, excites the associated circuits in a manner to be described.

The cathode is supported by a plurality of leads and supports l9 and arranged in a semicircle and extending through the end of the envelope. As best shown in Figures 1 and 3 the leads it are connected to a semi-circular conducting member 21. One of the leads I9 is electrically connected to the cathode H by strap H9. The heater lead 20 is spaced from the conductor 2! by means of the insulator 2D to permit a heating current to be applied to the heater 12 through the leads l9 and 20.

The grid is supported by means of the conductors 22 arranged in a semi-circle and electrically connected to the semi-circular conducting member 22'.

The circuits connected to the electrode system will now be described. A tubular conducting member 23, one end of which surrounds the en velope It! and is spaced closely adjacent the envelope and the collar of grid I3 is provided with a shielding partition 24 of conducting material dividing the member 23 into two shielded compartments. Within one compartment of this tubular member 23 is mounted a coaxial line type resonant cavity circuit connected to the cathode. It comprises an inner tubular member 25 and outer tubular member 26 connected together and closed at one end by the conducting member 27. The cathode and one side of the cathode heater line are connected through the lead I!) and conducting member 2! to the tubular member 25 by means of the spring clip 25. To supply heating current to the heater a clip 28 engages lead 20 and is electrically connected to and supported by the conducting plug 29, insulated from the tubular member 25 by the insulating collar 30, the other end of the plug being connected to conductor 3! which goes to the other side of the cathode heating circuit. This arrangement bypasses radio frequency voltages and currents and keeps them out of the cathode heater conductors. This concentric line circuit may be tuned by means of the tuning plunger 32 movable longitudinally by means of the rod 33. During operation parasitic oscillations may occur and these may be tuned out by means of a tuning condenser in the form of a ring 34 insulatingly supported on member 25 and movable longitudinally of the coaxial line circuit by means of the operating handle 35 extending through slot 36 in the members 23 and 26.

A grid circuit of the concentric type comprises the inner tubular member 31 surrounded by the coaxial tubular member 38, these members being electrically connected together and closed at one end by means of the conducting member 39. The free end of the member 31 adjacent the grid leads is closed by means of the metallic cup-shaped member 4i] and insulated from the tubular member 31 by insulating collar 4|. The conductor 42, by means of which a biasing voltage can be applied to the grid, is mounted within the tubular member 3? and electrically connected to the cap 40, the cap 40 being in turn connected to conducting member 22 by means of the spring clip 43 mounted on cap 40. This arrangement by-passes radio frequency voltages and currents which might otherwise flow into the grid voltage biasing circuit.

A tuning collar 44 operated by rod 45 can be moved along the coaxial tuning members in order to tune the grid circuit and to obtain certain results to be described. The partition 24 inserted within the tubular member 23, and extending close to the end of the envelope I E! shields the grid and cathode circuits from each other.

A third resonant cavity circuit is connected to the first accelerating electrode I! and comprises a tubular member 46 closed at one end by means of the conducting member 41, and forming with the member 23 a third coaxial line circuit. A rirg 48, having an L-shaped cross section is mounted within but insulated from the tubular member 46 b-yrneans of the insulating collar 49 which may be of mica. The cylindrical surfaces of member 48 and of member 46 together with the insulating collar 49 .form a radio frequency bypass condenser. An insulating ring 50 maintains the'members i and 23 in spaced relationship. In order to tune this last resonant cavity circuit for purposes to be described, I provide a tuning collar-or ring 5! of conducting material which may be slidably supported on the member 23 by means of the insulating flat ring members 52 and '53mounted within the member 5| and contacting the inner tubular member 23. The ring may be moved longitudinally by means of the insulating rod 54. This last circuit may be referred to as the accelerating electrode circuit. This last circuit is energized in a manner to be described by the modulated electron stream directed from the cathode to the collector.

1' The output tank circuit comprises a drumshaped resonant cavity tank circuit or resonator 55, the walls of which are electrically connected to collar shaped members 56 and 51, spaced by a gap 58. The members 56 and 5! serve as the output. electrodes in a manner now well known and described in my Patent 2,237,878 assigned to the same assignee as the present application. The member 56 is spaced from tubular member 23 and provides a second gap 59 in the accelerating electrode circuit. The conducting member 56 is electrically connected to the accelerator I! by means of the short radial leads 60 and spring clip members 5| so that the accelerator and output tank circuit can be maintained at the same potential.

In order to tune the output tank circuit I mount within the resonator 55 the conducting collar-like member 62 provided with the supporting lugs 53 pivoted at 64 to the insulating blocks or members 53' to which are connected the insulating operating rods 65 for varying the position of the ring longitudinally with respect to the gap 58 in the interior of the resonator.

To maintain the beam properly focused in its passage between the cathode II and the collector l8, I may provide solenoids 66 and 6'! for producing an electromagnetic field parallel to the movement of the electron beam.

To couple the output resonator 55 to a load 74, I provide an coaxial line coupling arrangement comprising tubular members 68 and 69, member 38 being closed by conductor 15. Enclosed within 69 is a second tubular member H telescopically receiving conducting rod 72 which may be moved longitudinally by means of insulating operating rod 72'. The position of the rod 12 within the member 58 determines the degree of coupling between the resonator and the coaxial line comprising elements 69 and H. As an additional means for properly matching the load impedance to the output impedance of the tube, I provide a tuning condenser 13, which can be moved along the concentric line 59'H. By properly positioning this condenser and adjusting the position of the coupling rod '12 an efficient coupling between the load and the output circuit of the tube is obtained.

In order to understand the problem and solution which my invention provides, reference may be had to Figure 4 which shows schematically the equivalent circuits of the input side of the electron discharge device made according to my invention. The output portion of the device is not shown in Figure 4.- The elements C, G and S represent, respectively, the cathode, control grid and screen which are denoted as electrodes ll, l3 and I! in Figure 1. The inductance Le represents the inductance of the leads l9 and 20, conductors 20' and the spring clips 25' and 28. The impedance Zc represents the impedance of the coaxial line tank comprising the elements 25, 26, 21' and tubular member 23. The capacity Cog represents the capacity between the cathode and grid I 3. The inductance Lg represents the lead inductance of the conductors 22, 22' and clip 43, and the impedance Zg represents the impedance of the coaxial line 31, 38 and 39 and that portion of the conductor 23 forming part of the grid circuit. The capacity Csg represents the capacity between the grid I 3 and accelerator and screen electrode [1. The impedance ZS is the impedance of the coaxial line tank circuit represented by tubular members 46, closure member 41 and tubular member 23 and member 48. The point A is indicated as the inner edge of the tubular member 23. Each of the coaxial lines can be tuned by the elements 32, 44 and 5|.

Thus by properly tuning the coaxial line tank circuit Zg the grid lead inductance Lg may be neutralized so that in effect the grid G may be at the same radio frequency potential as the point A. That is, the impedance between A and G can be made substantially zero. If this is done then the circuit Zss--Csg becomes substantially isolated from the circuit Zc-LcC-Ccg so that substantially no energy transfer can take place between these circuits. To minimize inductive and capacitive coupling between the cathode and grid lines the shield 24 is utilized. Now, if the cathode circuit GCc-gC-LeZe--A and the screen circuit G'CSg -S-'ZS' A are tuned in such a manner that they represent high impedance between points G and A, and if R.-F. energy is supplied from an external source to the cathode circuit, then the resulting cathode excitation will modulate the electron stream, which in turn, passing through the gap 59, will excite the screen circuit so that R.-F. voltage will appear at the gap 59. The mechanism by which the screen circuit will be excited by a modulated electron stream passing gap 59 is described in my patent referred to above. By properly tuning the screen circuit the phase and amplitude of voltage across gap 59 can be adjusted to attain the effect of phase focusing, described in my copending application, Serial No. 455,175, filed August 18, 1942, and assigned to the same assignee as the present application, and thus to obtr in high efiiciency of operation. In order to obtain high power gain when the tube is used as a stable amplifier, part of the energy extricated at gap 59 can be fed back to the cathode circuit, thus neutralizing to the desired degree the losses in the cathode circuit. The transfer of energy from the screen to the cathode circuit can be accomplished by a readjustment of the grid circuit G-LgZ --A, which controls the coupling between the screen and the cathode circuits. Instead of a previously described adjustment for complete isolation of these circuits, which was obtained when the grid circuit impedance between G and A was made substantially zero by tuning of the grid line, the line now is detuned from this position and now presents a finite impedance of a correct phase and magnitude suflicient to feed energy from screen to the cathode circuit and thus neutralize its lossses to the desired degree. This neutralization which is under control effected by tuning of the grid circuit can be made complete, if desired, in which case self-sustained oscillations will be generated in the system cathode-grid screen and the associated circuits. The electron stream after generating oscillations :in the G -G-S system retains its modinatio'n an'd'on passing gap 58 excites the output t'an k'circuit'55 to'which the load circuit is coupled. Thus this arrangement is equivalent to an electron coupled ultra-high frequency oscillator.

A more detailed schematic diagram of a por-' tion of the schematic circuit shown in Figure 4, namely, the grid circuit G-'L --'Z -A, is shown in Figure 5. The capacity between point A of the element 23 and the grid is represented by capacity C s. The inductance of the grid leads is Lg and the equivalent capacitance and inductance of the concentric line grid circuit are represented by C and L. The resistance of the grid circuit is represented by the element 1. For isolation of screen and cathode circuits the values or C and L are adjusted so (by tuning of plunger 44) the impedance from A to G is very low and is limited only by finite resistance 1' which can be made very low. However, for obtaining regenerative feedback of energy from screen to cathode circuit, the grid circuit from point A to point G must be represented by almost pure inductive reactance. Th presence of the capacitance Cga 'may limit, the range of inductive impedance which can be obtained by tuning of the grid circuit. Therefore, in the design of the tube the circuit capacitance of the control grid "and its'support i3 tothe cylinder A is made as'small as possible.

In Figure 6 is shown the schematic diagram of an electron discharge-device made according to my invention and the associated circuits. The cathode heater is supplied from an A, C. source through a transformer T5. The biasing voltage for the grid is supplied by means of the voltage source it, and the high voltage potential for the collector i i and the accelerators H and H; by means of the high voltage D. 'C. source 18. The biasing voltage source for maintaining the suppressor iii below the voltage of the collector M is indicated at 9. If operated as -a pulse transmitter the pulse voltage may be applied through the lead 'il. This pulse voltage in efiectneutralizes biasing voltage it for the period -'of the pulse length and permits the passage of current from the cathode H to collector it. Under these conditions the device is operated as an electroncoupled oscillatoras explained above, and pulses of -R.--F. energy are generated and delivered -to the load. If the device is to be operated as a radio frequency amplifier, a pulse voltage would not'beused to neutralize biasing voltage 'lfi. The .grid line would be tuned for optimum condition of regeneration as described above and the ex- ,citing voltage would be applied in the usual way by means of a coupling loop either within the cathode resonator or grid resonator, if desired.

The modulatedelectron beam in passing across the gap 58 excites the output resonator by induction in a manner described in my patent referred to above. In the present case I employ a. novel coupling arrangement for extracting-energy rromthe output resonator and matching the -:load impedance to the tube impedance. As pointed :out above, and referring to Figure l, by moving the rod '52 with respect te'the tubular member es the degree of coupling between the resonator and the coaxial line may be changed.

In effect this is similar to changing, for examplega tap 'on the conventional coil ofthe "conventional tank "circuit to "include more or less 8 turnsto increase or decrease the coupling and the amount or power't'aken from the tank circuit. 'By moving the rod 12 into the tubular member 68 the coupling may b increased but this at't'hesam'e time may vary the inductance and capacity of the coupling circuit. In order to match the impedance of the transmission line by the load, such as an antenna, to the tube impedance, a matching condenser 13 is used. This condenser 13 acts like a common coupling impedan c'e between the portion of the line-coupled into the resonator and theportioncoupled to the load. The position of the condenser I3 on the line TH69 can be varied by moving insulating rod 13 attached to condenser 13. Thus, the position of rod 12 determines the degree of coupling, and the proper positioning of condenser .13 neutrali'zes the reactive component of the coupling line 11. Thus, by proper matching maximum power output can be generated "and delivered to the useful load.

Thus :by means of my invention I have provided' an electron discharge device which is par,- ticularly useful at ultra high frequencies and in which the effect :of lead inductance and interelectrode capacitances have been neutralized to permit control of the operation of the device at high frequencies. :By means of my invention restrictions which were placed upon lead arrangements are removed and it is possible by individuallytuningeach of the circuits 'connected to the grid, cathode and accelerator to obtain the optimum performance. By means :of my invention -I have also eliminated the necessity for coaxial feed lines between the different circuits and the necessity for providing special phasing arrangements in the feedback coaxial lines. I have also provided by means of my invention a novel and efiective means for coupling the output of the resonator to a'load for maximum transfer of energy.

While I have indicated the preferred embodiments of my invention of which I am now aware and have also indicated only one specific application for whichmy invention may be employed, it will pe apparent that my invention is by no means limited-to theexactforms illustrated or the use indicated, but that many variations may be made in the particular structure used and thepurpose for which it is employed without departing from thescope-of my invention as set forth in the appended-claims.

What I-claim as new'is: 1. An electron discharge device having a cath- -ode,-acontrol electrode, and another electrode .all

tuning means =in said first cavity resonator for tuning-saidcavity resonator oil resonance, a second cavity resonator having one side coupled to .said other electrode, and --a common conductor -.having:substantially no reactance and electrically connecting the other sides-of said cavity resonators-together, said second cavity resonator surrounding said-first cavity resonator.

2. An electron discharge device having a cathode, control electrode, acceleratingelectrode and means for collecting electrons, all :in the order named, Fafirst' cavity resonator having one side coupled to said control electrode and :means included withisaid rfirst cavity resonator for tuning w'said ."fi'r-st cavity resonator soil resonance, a

second :cav'ity resonator having one side coupled to said accelerating electrode, and a common control electrode, and means included with said first cavity resonator for tuning said first cavity resonator, a third cavity resonator having one .side coupled to said accelerating electrode and a common conductor electrically connecting the other side of said second and third cavity resonators together.

4. An electron discharge device having a cath-. ode, control electrode, accelerating electrode and means for collecting electrons, all in the order named, a first cavity resonator having one side coupled to said control electrode, and means included with said first cavity resonator for tuning said first cavity resonator, a second cavity resonator having one side coupled to said accelerating electrode, and a common conductor electrically connecting the other sides of said first and second cavity resonators together, and means surroun ing the electron path for inductively extracting energy from electrons passing from said cathode to said collector.

5. An electron discharge device having a cathode, control electrode, accelerating electrode and means for collecting electrons, all in the order named, a coaxial line resonator connected to said control electrode and means included With said coaxial line resonator for tuning said coaxial line resonator, and a cavity resonator connected between said accelerating electrode and said coax al line cavity resonator.

6. An electron discharge device having a cathode, control electrode, accelerating electrode and means for collecting electrons, all in the order named, a first cavity resonator coupled to said control electrode, a second cavity resonator coupled to said cathode, and means included with said second cavity resonator for tuning said second cavity resonator, and a third cavity resonator coupled to said accelerating electrode, and conducting means common to and electrically connected to each of said first and third cavity resonators.

7. An electron discharge device having a cathode, control electrode, accelerating electrode, and collector, all in the order named. a first coaxial line resonator coupled to said cathode. a second coaxial line resonator coupled to said control electrode and a cavity resonator coupled between said accelerating electrode and the coaxial line resonator connected to said control electrode, and means included with the control electrode coaxial line c rcuit for tuning the coaxial line circuit connected to said control electrode.

8. An electron discharge device having a cathode, control electrode, accelerating electrode and collector in the order named, a first resonator having one side coupled to said cathode, a second resonator having one side coupled to said control electrode and means included with said second resonator for tuning said second resonator, a third resonator having one side coupled to said accelerating electrode, and a common conductor electrically connecting the other sides of said resonators together.

9. An electron discharge device having a cathode, control electrode, accelerating electrode and collector, all in the order named, a first coaxial line resonator connected to said cathode, and a second coaxial line resonator connected to said grid, and conducting means surrounding said coaxial line resonators and extending toward but spaced from said control electrode, and a cavity resonator coupled between said accelerating electrode and s id conducting means.

10. An electron discharge device having a cathode, control electrode, accelerating electrode and collector, all in the order named, a first coaxial line resonator coupled to said cathode, and a second coaxial line resonator coupled to said grid, and conducting means surrounding said coaxial l ne circu ts and extending toward but spaced from said control electrode, and a cavity resonator coupled between said accelerating electrode and said conducting means included with said second coaxial line resonator, and means for tuning said second coaxial line resonator.

11. An electron discharge device having a cathode, control electrode, accelerating electrode and collector, all in the order named, a first coaxial line resonator connected to said cathode, and a second coaxial line resonator connected to said grid. and conducting means surrounding said eoaxial line resonators and extending toward hut spaced from said control electrode, and a cavity resonator coupled between said accelerating electrode and said conducting means and including a tubular conductor surrounding said conducting means and connected thereto, and means included with said second coaxial line resonator for tuning said second coaxial line resonator.

12. An electron discharge device including an envelope having in the order named a cathode, control electrode and a third electrode, a first coaxial line resonator coupled to said cathode, and a second coax al line resonator coupled to said control electrode, and a cavity resonator coupled to said third electrode and surrounding said first and second coaxial line resonator, and means included with the second coaxial line resonator for tuning the second coaxial line resonator and means for collecting electrons from said cathode.

13. An electron discharge device including an envelope having in the order named a cathode, control grid, accelerating electrode and collector, leads positioned in a semi-circle extending through the end of said envelope and connected to said cathode, oppositely disposed leads positioned in a semi-circle and connected to th grid electrode, a coaxial line resonator, the inner conductor of which is coupled to said cathode leads, and a second coaxial line resonator, the inner conductor of which is coupled to said grid leads, said coaxial line resonators being paralel to each other, a tubular conducting member surrounding said coaxial line resonators and said cathode and grid leads and extending toward said grid, and a cavity resonator surrounding said tubular conducting member and coupled to said accelerating electrode and said tubular conducting member, and means for tuning the coaxial line resonator connected to said grid leads.

14. An electron discharge device including an envelope having in the order named a cathode, control grid, accelerating electrode and collector, leads positioned in a semi-circle extending through the end of said envelope and connected to said cathode oppositely disposed leads positioned in a semi-circle and connected to the grid electrode, a coaxial line resonator, the inner con ductor of which is coupled to said cathode leads, and a second coaxial line resonator, the inner conductor of which is coupled to said grid leads,

said coaxial line resonators being parallel to each other, a tubular conducting member surrounding said coaxial line resonators and said cathode and grid leads and extending toward said grid, and a cavity resonator surrounding said tubular conducting member and coupled to said accelerating electrode and said tubular conducting member, and means for tuning the coaxial line resonator connected to said grid leads, and a longitudinally extending shield positioned between said coaxial line resonators and contacting said tubular member on the interior thereof.

15. An electron discharge device including an envelope having in the order named a cathode, control grid, accelerating electrode and collector, a lead extending through the end of said envelope and connected to said cathode, a lead extending through said envelope and connected to said grid electrode, a first coaxial line resonator with one end coupled to said cathode lead, a second coaxial line resonator parallel to said first coaxial line resonator and coupled to said grid lead, a first tubular conducting member surrounding said coaxial line resonators and said leads and extending toward said control grid and close to said envelope, a second tubular conducting member surrounding said first tubular conducting member and forming therewith a cavity resonator, said cavity resonator being coupled to said accelerating electrode, and a cavity resonator positioned between said accelerating electrode and said cathode, and means for tuning the coaxial line resonator connected to said control grid lead.

16. An electron discharge device including an envelope having in the order named a cathode, control grid, accelerating electrode and collector, a lead extending through the end of said envelope and connected to said cathode, a lead exending through said envelope and connected to said grid electrode, a first coaxial line resonator with one end coupled to said cathode lead, a second coaxial line resonator parallel to said first coaxial line resonator and coupled to said grid lead, a first tubular conducting member surrounding said coaxial line resonator and extending toward said grid and close to said envelope, a second tubular conducting member surrounding said first tubular conducting member and forming therewith a cavity resonator, said cavity resonator being coupled to said accelerating electrode, and an output cavity resonator positioned between said accelerating electrode and said collector, and means for tuning each of the coaxial line resonators and said cavity resonator coupled to said accelerating electrode.

17. A cavity resonator including means for coupling said cavity resonator to a load, said means including a coaxial line, the outer conductor of said coaxial line communicating with th interior of said resonator, the free end of the inner conductor of said coaxial line extending within the space within the resonator, and hollow conducting means extending outside of said resonator, and oppositely disposed to the outer conductor of said coaxial line receiving the free end of the inner conductor when said inner conductor is adjusted to extend through the space within said resonator.

18. A cavity resonator including means for coupling said resonator to a load, said means including a coaxial line, the outer conductor of said coaxial line communicating with the interior of said resonator, the free end of the inner conductor of said coaxial line extending within the space within the resonator, and hollow conducting means extending outside of said resonator, and oppositely disposed to the outer conductor of said coaxial line receiving the free end of the inner conductor when said inner conductor is adjusted to extend through the space Within said resonator, and means within said coaxial line and movable longitudinally of the coaxial line for tuning said line.

19. An electron discharge device having a cathode, a cup-shaped control grid surrounding said cathode, an accelerating electrode and collector, a first coaxial line circuit having its inner conductor connected to said cathode, a second coaxial line circuit parallel to said first coaxial line circuit and having its inner conductor connected to said grid, a first tubular conducting member surrounding said coaxial line circuits and extending toward but spaced from said grid, a second tubular conducting member surrounding said first tubular conducting member and forming therewith a cavity resonator coupled between said accelerating electrode and said first tubular conducting member, and an output cavity resonator surrounding the path of the electrons from said cathode to said collector, and means for coupling said output cavity resonator to a load and comprising a coaxial line, the inner conductor of which has a free end extending into said output cavity resonator, said inner conductor being movable longitudinally of said output cavity resonator and adjustable tuning means in said last coaxial line for tuning said last coaxial line.

ANDREW V. HAEFF.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,312,723 Llewellyn Mar. 2, 1943 2,381,539 Hartley Aug. 7, 1945 2,272,211 Kohler Feb. 10, 1942 2,351,744 Chevigny June 20, 1944 2,311,520 Clifford Feb. 16, 1943 2,128,236 Dallenbach Aug. 30, 1938 2,167,201 Dallenbach July 25, 1939 2,309,966 Litton Feb. 2, 1943 2,329,773 Nergaard Sept. 21, 1943 2,304,186 Litton Dec. 8, 1942 2,306,860 Black Dec. 29, 1942 2,289,846 Litton July 14, 1942 2,259,690 Hansen et a1. Oct. 21, 1941 Disclaimer 2,432,571.-Andrew V. Haefl, Washingteh, D. C. ELECTRON DISCHARGE DEVICE EMPLOYING RESONATORS. Patent dated Dec. 16, 1947. Disclaimer filed Dec. 17, 1949, by the aSS1gnee,"Radi0 Corporation of America.

Hereby enters this disclaimer to claim 5 of said patent.

[Ojficz'al Gazette January 17, 1950,] 

